Sputum Bacterial Spectrum and Predominant Inflammatory Cells in Acute Exacerbations of COPD

This study was done to observe variation with seasons in sputum bacterial profile and predominant inflammatory cells in patients with AECOPD. Hundred sputum samples were cultured for bacteria and examined for type of inflammatory cells. Predominant bacteria and inflammatory cells and their variation with seasons were noted. Thirty six percent of sputum samples had bacterial growth. Bacterial growth was higher in summer and monsoon (43.3%) than in post- monsoon and winter period (21.2%) (p=0.031). Overall, Pseudomonas aeruginosa was the commonest organism cultured. In summer and post-monsoon, the commonest bacterium was Pseudomonas aeruginosa (16.6% and 15.4% respectively) and in monsoon, it was Klebsiella species (19.3%). Sputum neutrophilia (N>61%) was seen in 91% and sputum eosinophilia (E>3%) in 41% of the samples. There was no significant difference in the predominant inflammatory cells (N and N+ E) in sputum with seasons. Isolated sputum eosinophilia was higher in post- monsoon and winter than in summer and monsoon (12.1% v/s 7.5%, p=0.021). Length of hospital stay was less in patients with sputum eosinophilia than in patients with sputum neutrophilia (9.11v/s 10.12 days, p=0.023). Sputum neutrophilia was associated with higher sputum bacterial isolation. Eosinophilia in the sputum was likely to be associated with a sterile sputum. Bacterial isolation was higher in summer and monsoon than post- monsoon and winter. There was no significant difference in the predominant inflammatory cells with seasons. Sputum eosinophilia was associated with faster recovery from AECOPD than sputum neutrophilia